In most approaches, personalized medicine requires time- and cost-intensive characterization of an individual's genetic background in order to achieve the best-adapted therapy. For this purpose, cell-based drug delivery offers a promising alternative. In particular, synthetic biology has introduced the vision of cells being programmable therapeutic production facilities that can be introduced into patients. This review highlights the progress made in synthetic biology-based cell engineering toward advanced drug delivery entities. Starting from basic one-input responsive transcriptional or post-transcriptional gene control systems, the field has reached a level on which cells can be engineered to detect cancer cells, to obtain control over T-cell proliferation, and to restore blood glucose homeostasis upon blue light illumination. Furthermore, a cellular implant was developed that detects blood urate level disorders and acts accordingly to restore homeostasis while another cellular implant was engineered as an artificial insemination device that releases bull sperm into bovine ovarian only during ovulation time by recording endogenous luteinizing hormone levels. Soon, the field will reach a stage at which cells can be reprogrammed to detect multiple metabolic parameters and self-sufficiently treat any disorder connected to them.